pmeade
New Member
- Joined
- January 10, 2006
- Messages
- 3
- Reaction score
- 0
- City, State
- California
- Year, Model & Trim Level
- '94 LTD
I have a '94 LTD 4WD with 120k miles. It will start up and idles fine for about two minutes, then the idle gets rough. The CEL comes on regularly.
If I put it in drive or reverse it will usually stall out. When it stalls, I can immediately start it again. I can keep it going by giving it more gas, and can even get it up to higway speed. However, there is definitely a lot less power than usual.
I pulled the following error codes:
Key On Engine Off:
543 - Fuel Pump circuit open connection - Electronic Control Assembly to battery
Key On Engine Running:
172 - HEGO sensor - voltage indicates "lean" (Bank #1)
543 - Fuel Pump circuit open connection - Electronic Control Assembly to battery
Fuel pressure is between 32 and 38 PSI as tested near the FPR.
I've cleaned the MAF, put in a new fuel filter, and a new fuel pump relay. I checked my plugs and they all look fine (light gray)and my wires are about 1 year old. About six months ago I changed the O2 sensor on the passenger side because I was showing a 172 error - it never went away.
I have seen references on the internet where they say 543 is usually the fuel pump relay - I put in a brand new one, and have ruled it out also by jumpering pins 30 and 87. The fuel pump comes on and stays on.
I checked the vacuum hose from the fuel pressure regulator and it was dry, so I think the FPR is ok.
I think the next step would be to replace the fuel pump, but that is a lot of effort and I'd really hate to do it and find out it isn't the cause.
Any ideas??? I'm scratching my head with this one and would really appreciate any tips you can throw my way.
If I put it in drive or reverse it will usually stall out. When it stalls, I can immediately start it again. I can keep it going by giving it more gas, and can even get it up to higway speed. However, there is definitely a lot less power than usual.
I pulled the following error codes:
Key On Engine Off:
543 - Fuel Pump circuit open connection - Electronic Control Assembly to battery
Key On Engine Running:
172 - HEGO sensor - voltage indicates "lean" (Bank #1)
543 - Fuel Pump circuit open connection - Electronic Control Assembly to battery
Fuel pressure is between 32 and 38 PSI as tested near the FPR.
I've cleaned the MAF, put in a new fuel filter, and a new fuel pump relay. I checked my plugs and they all look fine (light gray)and my wires are about 1 year old. About six months ago I changed the O2 sensor on the passenger side because I was showing a 172 error - it never went away.
I have seen references on the internet where they say 543 is usually the fuel pump relay - I put in a brand new one, and have ruled it out also by jumpering pins 30 and 87. The fuel pump comes on and stays on.
I checked the vacuum hose from the fuel pressure regulator and it was dry, so I think the FPR is ok.
I think the next step would be to replace the fuel pump, but that is a lot of effort and I'd really hate to do it and find out it isn't the cause.
Any ideas??? I'm scratching my head with this one and would really appreciate any tips you can throw my way.